Sarsasapogenin is a steroidal sapogenin, that is the aglycosidic portion of a plant saponin. It is named after sarsaparilla (Smilax sp.), a family of climbing plants found in subtropical regions. It was one of the first sapogenins to be identified, and the first spirostan steroid to be identified as such. The identification of the spirostan structure, with its ketone spiro acetal functionality, was fundamental in the development of the Marker degradation, which allowed the industrial production of progesterone and other sex hormones from plant steroids.